The Turonian is, in the ICS

International Commission on Stratigraphy

The International Commission on Stratigraphy , sometimes referred to by the unofficial "International Stratigraphic Commission" is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigraphy, geological, and geochronological matters on a global...

' geologic timescale, the second age in the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 epoch

Epoch (geology)

An epoch is a subdivision of the geologic timescale based on rock layering. In order, the higher subdivisions are periods, eras and eons. We are currently living in the Holocene epoch...

, or a stage in the Upper Cretaceous series

Series (stratigraphy)

Series are subdivisions of rock layers made based on the age of the rock and corresponding to the dating system unit called an epoch, both being formally defined international conventions of the geological timescale. A series is therefore a sequence of rock depositions defining a...

. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma (million years ago). The Turonian is preceded by the Cenomanian

Cenomanian

The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...

 stage and underlies the Coniacian

Coniacian

The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...

 stage.

At the beginning of the Turonian an Anoxic event

Anoxic event

Oceanic anoxic events or anoxic events occur when the Earth's oceans become completely depleted of oxygen below the surface levels. Although anoxic events have not happened for millions of years, the geological record shows that they happened many times in the past. Anoxic events may have caused...

 took place which is called the Cenomanian-Turonian boundary event

Cenomanian-Turonian boundary event

The Cenomanian-Turonian boundary event, also known as the Cenomanian-Turonian extinction event, the Cenomanian-Turonian anoxic event, and referred to in Europe as the Bonarelli Event, was the latter of two anoxic extinction events early in the Late Cretaceous period...

 or the "Bonarelli Event".

Stratigraphic definition

The Turonian (French: Turonien) was definied by the French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 paleontologist Alcide d'Orbigny

Alcide d'Orbigny

Alcide Charles Victor Marie Dessalines d'Orbigny was a French naturalist who made major contributions in many areas, including zoology , palaeontology, geology, archaeology and anthropology....

 (1802 - 1857) in 1842. Orbigny named it after the French city of Tours

Tours

Tours is a city in central France, the capital of the Indre-et-Loire department.It is located on the lower reaches of the river Loire, between Orléans and the Atlantic coast. Touraine, the region around Tours, is known for its wines, the alleged perfection of its local spoken French, and for the...

 in the region of Touraine

Touraine

The Touraine is one of the traditional provinces of France. Its capital was Tours. During the political reorganization of French territory in 1790, the Touraine was divided between the departments of Indre-et-Loire, :Loir-et-Cher and Indre.-Geography:...

 (department Indre-et-Loire

Indre-et-Loire

Indre-et-Loire is a department in west-central France named after the Indre and the Loire rivers.-History:Indre-et-Loire is one of the original 83 départements created during the French Revolution on 4 March 1790...

), which is the original type locality

Type locality (geology)

Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....

.

The base of the Turonian stage is defined as the place where the ammonite

Ammonite

Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct subclass within the Molluscan class Cephalopoda which are more closely related to living coleoids Ammonite, as a zoological or paleontological term, refers to any member of the Ammonoidea an extinct...

 species Watinoceras devonense first appears in the stratigraphic column

Stratigraphic column

A stratigraphic column is a representation used in geology and its subfield of stratigraphy to describe the vertical location of rock units in a particular area....

. The official reference profile (the GSSP) for the base of the Turonian is located in the Rock Canyon anticline near Pueblo, Colorado

Pueblo, Colorado

Pueblo is a Home Rule Municipality that is the county seat and the most populous city of Pueblo County, Colorado, United States. The population was 106,595 in 2010 census, making it the 246th most populous city in the United States....

 (USA, coordinates: 38° 16' 56" N, 104° 43' 39" W).

The top of the Turonian stage (the base of the Coniacian) is defined as the place in the stratigraphic column where the inoceramid

Inoceramidae

Inoceramidae was a family of prehistoric clams. Inoceramids tended to live in upper bathyal and neritic environments. In Alaska's Matanuska Formation, the most abundant mollusks in the quarry containing the Talkeetna Mountains Hadrosaur were inoceramids....

 bivalve species Cremnoceramus rotundatus first appears.

Subdivision

The Turonian is sometimes subdivided in Lower/Early, Middle and Upper/Late substages or subages. In the Tethys domain

Tethys Ocean

The Tethys Ocean was an ocean that existed between the continents of Gondwana and Laurasia during the Mesozoic era before the opening of the Indian Ocean.-Modern theory:...

, it contains the following ammonite biozone

Biozone

Biostratigraphic units or Biozones are intervals of geological strata that are defined on the basis of their characteristic fossil taxa....

s:

• zone of Subprionocyclus neptuni (in the Upper Turonian)
• zone of Collignoniceras woollgari
  Collignoniceras
  Collignociceras is an evolute, strongly ribbed and tuberculate ammonoid from the Upper Cretaceous of the western United States and Europe belonging to the ammonite family Collignoniceratidae. The type is Ammonites woollgari, named by Mantell in 1822 for specimens from Sussex, England.Wright...
  
  (in the Middle Turonian)
• zone of Mammites nodosoides
  Mammites
  Mammites is an Upper Cretaceous ammonite belonging to the acanthoceratacean family, Acanthoceratidae, and is the type genus for the subfamily Mammitinae. It was named by Laube and Bruder in 1887. It range is Lower to Upper Turonian....
  
  
• zone of Watinoceras coloradoense or Watinoceras devonense (last two both in the Lower Turonian)

Other important index fossil

Index fossil

Index fossils are fossils used to define and identify geologic periods . They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil...

s are species of the inoceramid genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Inoceramus

Inoceramus

Inoceramus is an extinct genus of fossil marine pteriomorphian bivalves that superficially resembled the related winged pearly oysters of the extant genus Pteria....

(I. schloenbachi, I. lamarcki and I. labiatus). Inoceramids are bivalve Mollusca

Mollusca

The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...

 related to todays mussels.

†Ankylosaurs

Ankylosaurs Ankylosauria Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. They are first known to have appeared in the early Jurassic Period of...  of the Turonian
Taxa	Presence	Location	Description	Images
Aniksosaurus Aniksosaurus Aniksosaurus was a genus of dinosaur from what is now present-day Chubut Province, Argentina. It was a theropod, specifically a coelurosaur, which lived in the middle Cretaceous period...
Maleevus Maleevus Maleevus is a genus of ankylosaurid dinosaur that is known only from the jawbone and part of the skull discovered in 1952 by Soviet palaeontologist Evgenii Aleksandrovich Maleev. It has been estimated that Maleevus was about 6 meters long...
Talarurus Talarurus Talarurus is a genus of hippopotamus-sized ankylosaurid dinosaur with heavy armour and a club tail. It was named by Evgeny Maleev in 1952.-Age and location:...		Bayn Shire Formation, Mongolia

Birds

Aves of the Turonian
Taxa	Presence	Location	Description	Images
Catenoleimus Catenoleimus Catenoleimus is a prehistoric bird genus from the Late Cretaceous. It lived during the mid-late Turonian stage, around 90 million years ago...		Bissekty Formation Bissekty Formation The Bissekty Formation is situated in the Kyzyl Kum desert of Uzbekistan, and dates from the late Cretaceous Period. Laid down in the early the Turonian to Coniacian stages, it is dated to about 90-85 ma .The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and... , Uzbekistan	A mid-sized enantiornithine, perhaps 20-25 cm long in life
Explorornis Explorornis Explorornis is a genus of Mesozoic birds. It lived during the mid-late Turonian stage, around 90 million years ago.Unlinke many contemporary genera, which are only known from a handful of remains that cannot be compared among each other, Explorornis is known from a handful of coracoids which are...		Bissekty Formation Bissekty Formation The Bissekty Formation is situated in the Kyzyl Kum desert of Uzbekistan, and dates from the late Cretaceous Period. Laid down in the early the Turonian to Coniacian stages, it is dated to about 90-85 ma .The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and... , Uzbekistan
Ichthyornis Ichthyornis Ichthyornis is a genus of toothed seabirds from the Late Cretaceous of North America. Its fossil remains are known from the chalks of Alberta, Alabama, Kansas, New Mexico, Saskatchewan, and Texas, in strata that were laid down in the Western Interior Seaway during the Turonian-Campanian ages,...	Turonian - Campanian Campanian The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...	Alberta and Saskatchewan, Canada; Alabama, Kansas, New Mexico and Texas, USA; Argentina; Central Asia	The Cretaceous ecological equivalent of modern seabirds such as gulls, petrels, and skimmers. At 60 cm (2 ft), it was the size of a gull. Although the wings and breastbone are very modern in appearance (suggesting strong flight ability), the jaws retained numerous small, sharp teeth

†Ceratopsians

Ceratopsia Ceratopsia Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs which thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7...  of the Turonian
Taxa	Presence	Location	Description	Images
Zuniceratops Zuniceratops Zuniceratops was a ceratopsian dinosaur from the mid Turonian of the Late Cretaceous Period of what is now New Mexico, United States...		Moreno Hill Formation Moreno Hill Formation The Moreno Hill Formation is a geological formation in New Mexico whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Dinosaurs:-References:... , New Mexico, USA	The earliest-known ceratopsian to have eyebrow horns and the oldest-known ceratopsian from North America, appears to have been roughly 3 to 3.5 meters long (10-11 ft) and 1 meter (3 ft) tall at the hips.

Crocodylomorphs

Crocodylomorpha Crocodylomorpha The Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...  of the Turonian
Taxa	Presence	Location	Description	Images
Baurusuchus Baurusuchus Baurusuchus is an extinct genus of baurusuchid mesoeucrocodylian from the Late Cretaceous of Brazil. It was a terrestrial predator and scavenger, about 3.5 to 4 meters long. Baurusuchus lived during the Turonian to Santonian stages of the Late Cretaceous Period, in Adamantina Formation, Brazil...
Montealtosuchus Montealtosuchus Montealtosuchus was an extinct genus of terrestrial crocodyliform. It was discovered in 2004 in the Bauru Basin of Brazil, from Turonian-Santonian deposits of the Adamantina Formation. The species was described in 2007, and assigned to the family Peirosauridae. The type species is M. arrudacamposi...	Turonian to Santonian Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...	Adamantina Formation Adamantina Formation The Adamantina Formation is a geological formation in Brazil whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation... , São Paulo, Brazil	A terrestrial Peirosaurid
Stratiosuchus

Mammals

Mammalia of the Turonian
Taxa	Presence	Location	Description	Images
Bryceomys Bryceomys Bryceomys is an extinct mammal that lived during the late Cretaceous period and thus shared the world with dinosaurs. It was a member of the also extinct order of Multituberculata...

†Ornithopods

Ornithopoda of the Turonian
Taxa	Presence	Location	Description	Images
Bactrosaurus Bactrosaurus Bactrosaurus is a genus of herbivorous dinosaur that lived in east China during the late Cretaceous, about 70 mya. The position Bactrosaurus occupies in the Cretaceous makes it one of the earliest known hadrosaurs, and although it is not known from a full skeleton, Bactrosaurus is one of the best...	Turonian to Coniacian Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...	Gobi Desert Gobi Desert The Gobi is a large desert region in Asia. It covers parts of northern and northwestern China, and of southern Mongolia. The desert basins of the Gobi are bounded by the Altai Mountains and the grasslands and steppes of Mongolia on the north, by the Hexi Corridor and Tibetan Plateau to the... , Mongolia and China	Would have been 6 m (20 ft) long[1] and 2 m (7 ft) high when in the quadrupedal stance, and weighed 1100 - 1500 kg (2400 - 3300 lb). Like many hadrosaurs, it could switch between bipedal and quadrupedal stances, but unusually it had large spines protruding from the vertebrae.
Macrogryphosaurus Macrogryphosaurus Macrogryphosaurus is a genus of basal iguanodont dinosaur from the Turonian-early Coniacian age Upper Cretaceous Portezuelo Formation of Patagonia, Argentina. It was described by Jorge Calvo and colleagues, with M...	Turonian to early Coniacian Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...	Portezuelo Formation Portezuelo Formation The Portezuelo Formation is a geologic formation outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina. It is the fourth-oldest formation in the Neuquén Group and the older of the two formations in the Río Neuquén Subgroup... , Argentina	A genus of basal iguanodont, a large bipedal herbivor
Notohypsilophodon Notohypsilophodon Notohypsilophodon was a genus of hypsilophodont ornithopod dinosaur. It was described as the only hypsilophodont known from South America, although this assessment is not universally supported, and Gasparinisaura is now believed to have been a hypsilophodont as well...	Cenomanian Cenomanian The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding... -Turonian	Bajo Barreal Formation Bajo Barreal Formation The Bajo Barreal Formation is a geological formation in Chubut, Argentina whose strata date back to the Late Cretaceous.-Dinosaurs:Dinosaur remains are among the fossils that have been recovered from the formation... , Chubut, Argentina	A hypsilophodontid or other basal ornithopod, Notohypsilophodon would have been a bipedal herbivore. Its size has not been estimated
Shuangmiaosaurus Shuangmiaosaurus Shuangmiaosaurus is a genus of herbivorous ornithischian dinosaur which lived during the late Albian age of the Early Cretaceous Period, about 100 million years ago. It was an iguanodont euornithopod which lived in China....	Cenomanian Cenomanian The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding... -Turonian	China	A poorly known iguanodont Iguanodont Iguanodonts were herbivorous dinosaurs that lived from the mid-Jurassic to Late Cretaceous. Some members include Camptosaurus, Callovosaurus, Iguanodon, Ouranosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodonts were one of the first groups of dinosaurs to be found...

†Plesiosaurs

Plesiosauria Plesiosauria Plesiosauria is an order of Mesozoic marine reptiles. Plesiosaurs first appeared in the Early Jurassic Period and became especially common during the Jurassic Period, thriving until the K-T extinction at the end of the Cretaceous Period.The name "plesiosaur" is used to refer to the order...  of the Turonian
Taxa	Presence	Location	Description	Images
Libonectes Libonectes Libonectes is an extinct genus of sauropterygian reptile belonging to the plesiosaur order. It is known from a single fossil specimen found in the Britton Formation of Texas, dated to the lower Turonian stage of the late Cretaceous period.The animal was very similar to the related Thalassomedon,...		Britton Formation Britton Formation The Britton Formation is a Mesozoic geologic formation. Plesiosaur remains are among the fossils that have been recovered from its strata....  (Cedar Hill Cedar Hill, Texas Cedar Hill is a city in Dallas and Ellis Counties in the U.S. state of Texas. It is located approximately sixteen miles southwest of downtown Dallas and is situated along the eastern shore of Joe Pool Lake and Cedar Hill State Park. The population was 32,093 at the 2000 census... ), Texas, USA	A 7-14 m (23-47 ft) long creature, was very similar to the related Elasmosaurus Elasmosaurus Elasmosaurus + σαυρος sauros 'lizard') is a genus of plesiosaur with an extremely long neck that lived in the Late Cretaceous period , 80.5 million years ago.-Description:... . It had a compact body with a short tail and large flippers. Its small skull had long, forward-facing teeth ideal for catching slippery fish and squid that came together outside of its mouth when the mouth was closed, and was placed atop a very long neck.
Manemergus Manemergus Manemergus is a genus of polycotylid plesiosaur from the Late Cretaceous of Morocco. Manemergus was described in 2005 and contains only one species, M. anguirostris...		Morocco	A genus of polycotylid plesiosaur
Polyptychodon Polyptychodon Polyptychodon is an extinct genus of sauropterygian reptile belonging to the family Pliosauridae that lived during the Cretaceous. Its fossils have been found in Europe and North America.... hudsoni		Texas, USA
Thililua Thililua Thililua is a genus of polycotylid plesiosaur, containing one species, T. longicollis. The name Thililua is derived from that of an ancient aquatic god from local Berber mythology; longicollis refers to the animal's long neck. Thililua has been found in Late Cretaceous rocks in the High Atlas...		High Atlas High Atlas High Atlas, also called the Grand Atlas Mountains is a mountain range in central Morocco in Northern Africa.The High Atlas rises in the west at the Atlantic Ocean and stretches in an eastern direction to the Moroccan-Algerian border. At the Atlantic and to the southwest the range drops abruptly... , Morocco	A genus of polycotylid plesiosaur, the estimated total length of Thililua is 5.5 to 6 metres.

Squamats

Squamata Squamata Squamata, or the scaled reptiles, is the largest recent order of reptiles, including lizards and snakes. Members of the order are distinguished by their skins, which bear horny scales or shields. They also possess movable quadrate bones, making it possible to move the upper jaw relative to the...  of the Turonian
Taxa	Presence	Location	Description	Images
Dallasaurus Dallasaurus Dallasaurus is a basal mosasauroid from the Upper Cretaceous of North America. The genus is based upon two partial skeletons recovered from the Arcadia Park Shale , approximately 15 meters above its contact with the older Kamp Ranch Limestone in Dallas County in north-central Texas...		Arcadia Park Shale, Texas, USA	A basal, small, plesiopedal mososauroid
Russellosaurus Russellosaurus Russellosaurus is a basal mosasauroid from the Upper Cretaceous of North America. The genus was described from a skull discovered in an exposure of the Arcadia Park Shale at Cedar Hill, Dallas County in south-central Texas...		Arcadia Park Shale, Texas, USA	A basal, small, lightly built mosasaur

†Theropods (non-avian)

Theropods Theropoda Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...  of the Turonian
Taxa	Presence	Location	Description	Images
Bayosaurus Bayosaurus "Bayosaurus" is the informal name given to an as yet undescribed genus of dinosaur. The name was coined by paleontologists Rodolfo Coria, Philip J. Currie, and Paulina Carabajal in 2006. "Bayosaurus" appears on several on-line lists of dinosaurs...
Giganotosaurus Giganotosaurus Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived around 97 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It included some of the largest known terrestrial carnivores, slightly larger than the largest Tyrannosaurus, but smaller than the...		Rio Limay, Argentina
Nothronychus Nothronychus Nothronychus is a genus of theropod dinosaur classified in the group Therizinosauria, from the Cretaceous of North America.The type species of this dinosaur, Nothronychus mckinleyi, was described by James Kirkland and Douglas G. Wolfe in 2001...
Urbacodon Urbacodon Urbacodon is a genus of troodontid dinosaur, a type of small carnivore. It lived in Uzbekistan during the early Late Cretaceous Period, about 95 million years ago. The first part of the name Urbacodon is an acronym, honouring the Uzbek, Russian, British, American and Canadian scientists who...

Literature

; 2004: A Geologic Time Scale 2004, Cambridge University Press

Cambridge University Press

Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

.; 2005: The Global Boundary Stratotype Section and Point for the base of the Turonian Stage of the Cretaceous: Pueblo, Colorado, U.S.A., Episodes 28(2): pp 93-104.

External links

• GeoWhen Database - Turonian
• Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
• Stratigraphic charts of the Cretaceous: http://norges.uio.no/timescale/Fig18.1_Cret_colA.pdf and http://norges.uio.no/timescale/Fig18.1_Cret_colB.pdf, at the website of Norges Network of offshore records of geology and stratigraphy
• Turonian Microfossils: 48 images of Foraminifera